#include<iostream>

using namespace std;

inline int isNumber(char c) {return (c >= '0' && c <= '9') ? 1 : 0;}

int main () {
    char c;
    cin >> c;
    if (isNumber(c)) {
        cout << "You entered a digit" << endl;
    } else {
        cout << "You entered a non-digit" << endl;
    }
}
